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May 13 - 16, 2008 |
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Extrusion/Die Practical 023 PR The Use of Gaseous Nitrogen to Improve the Surface Finish of Dilute 6xxx Extrusions Martin Fortier, Dominique Lavoie, and Nick Parson -- Alcan International Ltd., Canada, and Chris Jowett -- Consultant, Canada Liquid nitrogen may improve surface finish, die life and extrusion speed, but it is expensive, and its efficacy is questionable. Cheaper nitrogen gas offers no significant cooling, but creates an inert atmosphere at the die exit. Gaseous nitrogen benefits 7xxx and medium-strength 6xxx alloys; beneficial effects on AA6063 and faster pushing 6xxx alloys (AA6060/AA6360) are uncertain. Quantifying gaseous nitrogen’s benefits with dilute alloys is presented. |
